Most types of computer systems which are in use today require the ability to store large amounts of data for ready access by system users. Data storage media technology has exhibited great advances in the last few years such that large amounts of data are able to be stored on computer systems. Several examples of data storage media in use today are floppy disks, hard disks, optical disks, magnetic tape, as well as other data storage devices.
It is known by those with skill in the art that information stored on data storage devices must be readily changed or updated either by a user or by another system as external conditions demand data updating. When a limited number of users have access to a database, or when the time for database updating is not critical, there is little problem in updating the storage medium with new information. However, when a database is being continually accessed or when a variety of users need access to the database for different information, it has generally been undesirable to take large amounts of time for updating the database but, desirable to provide efficient storage of a wide variety of data on the database so that many different users can be accommodated. There has been a long-felt need in the art for near optimal storage of data on databases thereby reducing access time by users to information on the database and providing efficient data updating.
In order to store extremely large amounts of data on a database, it is often necessary to use a mass storage medium such as, for example, magnetic tape, floppy disks, hard disks and optical disks, etc. Mass storage media are generally "access time variant" (ATV). As herein defined and used throughout, an "ATV" medium refers to any type of data storage medium wherein the last access of data stored on the medium influences the access time to the next item stored on the medium. It is usually extremely desirable to keep the access time to all items on the ATV medium as low as possible. The access time to data items on an ATV medium is determined by the time it takes the particular accessing means of the ATV medium to locate the requisite data item stored on the ATV medium. Maximum access time occurs when two consecutive pieces of data to be accessed reside at the most remote positions from one another on the ATV medium. Maximum access time can be empirically determined for any ATV medium by measuring all possible access times from prior datum to subsequent datum.
Certain prior art approaches have been utilized to retrieve information stored on a tape for display by a computer or on a video screen. U.S. Pat. No. 3,757,037, Bialek embodies such a system. The device embodied in the Bialek patent requires that information stored on a video cassette be grouped. See Bialek column 1, line 25. Some A priori knowledge of where to place and group related data is necessary to utilize the device embodied in the Bialek patent. Thus, Bialek fails to provide a computer database which is efficiently useful to a large variety of users, since grouping of information for fast access can only be tailored for specific individual user's tastes.
Another prior art approach to creating a database containing information which is available to a variety of users is embodied in U.S. Pat. No. 4,450,477, Lovett. The device disclosed in the Lovett patent shows a television information system which transmits selected video picture information to a number of subscribers who have televisions connected to the system. See Lovett, column 6, lines 40-45. According to the operation of the Lovett system, a subscriber makes a selection from the system by transmitting a request to the database. See Lovett, column 7, lines 10-15. A central computer having a central database searches the database for the information and sends it over a carrier frequency which has been specifically dedicated to the specific subscriber.
The device embodied in Lovett requires that each user be given a specific television frequency for interfacing with a complex central database. The inventors of the subject matter disclosed and claimed herein have determined that the most economical and efficient way for many users to optimally access data on a database is to distribute the databases among the individual users. The databases distributed among the individual users can then be continuously updated according to an optimal updating algorithm. The device in the Lovett patent fails to provide any of these features. Thus, the device in Lovett does not satisfy the long-felt need in the art for an economical and efficient database which can be used in the homes of a multitude of users.
It has been known in the computer art to provide remote terminals which can communicate with a central database and computer system. See U.S. Pat. No. 4,658,290, McKenna et al. The device embodied in the McKenna et al. patent discloses a data storage and transmission system for accumulating data and transmitting the data to a central location. See column 1, lines 18-21 of McKenna et al. However, the device described and disclosed in the McKenna et al. patent merely transmits statistics about television viewing habits and product purchases of selected users by transmitting information to the central database over a cable line. The device in the McKenna et al. patent does not provide for continuous and optimal updating of data in remote databases which can be used by a large number of subscribers. Thus, the device embodied in the McKenna et al patent does not fulfill the long-felt need in the art for distributed databases with optimal data storage.
Periodic updating of information which is displayed to subscribers through a video display device has also been known in the computer art. See U.S. Pat. No. 4,203,130, Doumit et al. The Doumit patent discloses a device which updates data from a central database periodically. See Doumit et al. column 2, lines 11-15. However, the system disclosed in Doumit provides globally updated information to all users of the system in a single order and format. Thus, the device disclosed and described in Doumit et al can not provide optimally updated data to a multiplicity of remote databases when different users of the remote databases have unique data access habits.
The inventors have recognized a long-felt need in the art for a computer system having databases distributed among a potentially unlimited number of users. The information stored in all of the databases must be continuously updated and optimally placed on an ATV storage medium according to the desires and access habits of each the particular user. The inventors have also recognized a long-felt need in the art for systems which display optimally updated data which has been stored according to a user's particular statistical data access habits. The inventors have invented methods and systems which solve these problems and fulfill the aforementioned long-felt needs in the computer art for systems and methods for optimal updating of data.